ethers.js/utils/units.js

133 lines
3.4 KiB
JavaScript

var bigNumberify = require('./bignumber.js').bigNumberify;
var throwError = require('./throw-error');
var zero = new bigNumberify(0);
var negative1 = new bigNumberify(-1);
var names = [
'wei',
'kwei',
'Mwei',
'Gwei',
'szabo',
'finny',
'ether',
];
var getUnitInfo = (function() {
var unitInfos = {};
var value = '1';
names.forEach(function(name) {
var info = {
decimals: value.length - 1,
tenPower: bigNumberify(value),
name: name
};
unitInfos[name.toLowerCase()] = info;
unitInfos[String(info.decimals)] = info;
value += '000';
});
return function(name) {
return unitInfos[String(name).toLowerCase()];
}
})();
function formatUnits(value, unitType, options) {
if (typeof(unitType) === 'object' && !options) {
options = unitType;
unitType = undefined;
}
if (unitType == null) { unitType = 18; }
var unitInfo = getUnitInfo(unitType);
// Make sure wei is a big number (convert as necessary)
value = bigNumberify(value);
if (!options) { options = {}; }
var negative = value.lt(zero);
if (negative) { value = value.mul(negative1); }
var fraction = value.mod(unitInfo.tenPower).toString(10);
while (fraction.length < unitInfo.decimals) { fraction = '0' + fraction; }
// Strip off trailing zeros (but keep one if would otherwise be bare decimal point)
if (!options.pad) {
fraction = fraction.match(/^([0-9]*[1-9]|0)(0*)/)[1];
}
var whole = value.div(unitInfo.tenPower).toString(10);
if (options.commify) {
whole = whole.replace(/\B(?=(\d{3})+(?!\d))/g, ",")
}
var value = whole + '.' + fraction;
if (negative) { value = '-' + value; }
return value;
}
function parseUnits(value, unitType) {
var unitInfo = getUnitInfo(unitType || 18);
if (!unitInfo) { throwError('invalid unitType', { unitType: unitType }); }
if (typeof(value) !== 'string' || !value.match(/^-?[0-9.,]+$/)) {
throwError('invalid value', { input: value });
}
// Remove commas
var value = value.replace(/,/g,'');
// Is it negative?
var negative = (value.substring(0, 1) === '-');
if (negative) { value = value.substring(1); }
if (value === '.') { throwError('invalid value', { input: value }); }
// Split it into a whole and fractional part
var comps = value.split('.');
if (comps.length > 2) { throwError('too many decimal points', { input: value }); }
var whole = comps[0], fraction = comps[1];
if (!whole) { whole = '0'; }
if (!fraction) { fraction = '0'; }
// Prevent underflow
if (fraction.length > unitInfo.decimals) {
throwError('too many decimal places', { input: value, decimals: fraction.length });
}
// Fully pad the string with zeros to get to wei
while (fraction.length < unitInfo.decimals) { fraction += '0'; }
whole = bigNumberify(whole);
fraction = bigNumberify(fraction);
var wei = (whole.mul(unitInfo.tenPower)).add(fraction);
if (negative) { wei = wei.mul(negative1); }
return wei;
}
function formatEther(wei, options) {
return formatUnits(wei, 18, options);
}
function parseEther(ether) {
return parseUnits(ether, 18);
}
module.exports = {
formatEther: formatEther,
parseEther: parseEther,
formatUnits: formatUnits,
parseUnits: parseUnits,
}